For its first 40 minutes, Riddick, the third installment in the film series tracking the actions of unrepentant criminal and all-around cosmic badass John Riddick, is strangely fascinating. During that stretch, the titular character (played with typical lunkheaded bravado by Vin Diesel) is the only human on screen, wandering a wasteland-like planet and fighting off a variety of CGI creatures that inhabit it. The section has a very Cast Away quality to it, with Riddick reverting back to prehistoric wiles to stay fed, in shape, and alive. It’s when more characters are introduced that things get ugly, stupid, and disturbing.

Riddick hails this batch of folks — a group of bounty hunters, and a cadre of interstellar police — from an abandoned outpost on the planet in hopes of getting a ride off the unforgiving rock. But as one group wants his literal head, and the other is searching for answers, the cat and mouse games begin and copious amounts of blood are spilled.

In the hands of a more capable writer/director, this is the foundation for a fine thriller. But with David Twohy (who directed and co-wrote the previous two installments), it’s a chance to truck out some of the worst dialog and most stereotypical characters ever committed to film. To give him some credit, the 57-year-old filmmaker only provides a smattering of exposition, especially in regards to one of the biggest threats all these characters face. It’s a daring move, but the only moment where Twohy pretends that his audience is as smart as he is.

Riddick is never more doltish than when it comes to its treatment of the film’s sole female character. (There are a few of other women in the picture, but they are used first as nude eye candy and then as cannon fodder.) Played by Katee Sackhoff of Battlestar Galactica fame, Dahl spends the film spouting awful lines, beating up the head bounty hunter, and loudly announcing her homosexuality. Twohy, though, makes sure to slowly undercut any strength she initially have. First, she spends a few minutes topless, then reveals some daintily painted toenails. And, of course, by the end, she’s more than willing to jump in the sack with Riddick.

All of the above missteps could have been ignored would Twohy and his post-production crew managed to make the external universe more wowing. Instead, wide shots have a smeared, pixelated quality to them, and the creatures of this desert-like planet look like they were created as afterthoughts. There’s, of course, not much chance that anyone ponying up to attend see Riddick on the big screen is expecting greatness. But a spoonful of CGI sugar or thoughtful dialog sure would have made the bitter medicinal tang of this film go down a lot easier.